It is common practice to provide utilities, such as water or gas supply or other services including waste water drainage/sewerage along underground pipes. This reduces the obstruction caused by these pipes, particularly in crowded urban areas. It can also provide the pipes with some measure of protection against environmental exposure.
Along with these advantages, there are some disadvantages, in particular, the possibility of damage to the pipes from ground movement, subsidence, increased overhead traffic, tree growth or the like. Another problem with underground pipes is the inconvenience of uncovering or accessing pipes for repair. The access and repair issue has been addressed by inserting a pipe liner, typically formed from a rigid polymer material, along a section of underground pipe. The liner can provide additional structural support for the pipe and may seal cracks, holes or the likes in the existing pipe. Typically, the pipe liner is preformed in a shape substantially corresponding to that of the pipe, but with a slightly narrower diameter. The liner can then be inserted into the pipe. Once in situ, heat expansion can be used to expand the liner into a close fit with the inner surface of the pipe. An alternative method known as swage lining involves reducing the diameter of a liner by pulling it through a die before inserting into a pipe. After insertion, the line will gradually expand back to its original diameter and thereby form a close fit with the inner surface of the pipe.
A further alternative method involves soaking an absorbent fabric pipe liner in resin, inserting said fabric pipe liner into the pipe, pressing the liner against the pipe surface and curing the resin. Typically, the resin is either left to cure gradually or the curing is accelerated using heat and/or ultraviolet light. Where the process is accelerated this can require large amounts of power. There are many variants on such cured in place polymer (CIPP) pipe lining systems, nevertheless, each suffers from the fact that the resin components are typically toxic. As such, soaking the liner material with resin may require a specialised equipment or facilities. Additionally, CIPP liners tend to be very rigid once cured and thus provide minimal flexibility to accommodate subsequent ground or pipe movements.
Whilst the above methods provide for convenient repair/renewal of a pipe, it can be complex and/or costly to apply such a method in many situations. In particular, such preformed liners have limited flexibility which can cause difficulty if the pipe includes multiple bends, variations in diameter. Additional problems may be caused where there are other irregularities in the interior surface of the pipe (from collapse or otherwise) or if there is restricted access to the pipe section to be repaired/renewed. A further significant problem with such liners is storage and convenience of transport or handling. Since the liners typically have limited flexibility, storage and deployment is possible only off a relatively large spindle. Additionally, storage of liners is volumetrically inefficient in view of the significant empty inner volume of the liner.
It is therefore an object of the present invention to provide an improved pipe liner, method of installing a pipe liner and apparatus for installing a pipe liner that overcome or at least alleviate some of the above issues.